48 is not that high. It is way too early to suggest surgery.
The next step would be a Protein C test, then scintigraphy, depending on the results. (Don't do an ultrasound. They are
at best only 80% effective at detecting shunts.)
You may very likely be dealing with asymptomatic MVD which is very common and should not cause any problems.
Here is a link for you from Dr. Center who developed the bile acids test:
Hepatic Vascular Disorders - WSAVA 2006 Congress